Einstein's General Theory of Relativity about matter, space, gravity and time seems incompatible with the theory of quantum mechanics, which governs the microworld of quarks and leptons. Physicists have been searching for ways to make a bridge the two worlds. In 1999, Lisa Randall of Harvard and Raman Sundrum of Johns Hopkins University co-authored two of the most important scientific papers on extra spatial dimensions, explaining how our visible world of four dimensions could be embedded in a higher-dimensional universe.

Randall's work has influenced advocates of string theory, and technology may be coming closer to verifying string theory, which she presents in her book, Warped Passages: Unraveling the Mysteries of the Universe's Hidden Dimensions. Proof of an extra dimension could occur when the new Large Hadron Collider in Geneva, Switzerland begins operations next year, it may have enough energy to produce particles that travel in or through an extra dimension, or even produce microscopic black holes.